Baeyer-Villiger oxidation of ketones with a silica-supported peracid in supercritical carbon dioxide under flow conditions

[2-Percarboxyethyl]-functionalized silica reacts with ketones in supercritical carbon dioxide at 250 bar and 40 degrees C under flow conditions to yield the corresponding esters and lactones. The solid reagent can be easily recycled through treatment with 70% hydrogen peroxide in the presence of an acid at 0 degrees C. This procedure not only simplifies the isolation of the reaction products, but has the advantage of using only water and carbon dioxide as solvents under mild conditions.